530 
A gricultural Possibilities. 
[September, 
attempt to show that chemical manures, if properly selected 
and applied, are more efficient and cheaper than farm-yard 
manure. This he proves by a perfedf multitude of experi- 
ments made by different persons, in various parts of France, 
and upon soils of very different quality. Almost without 
exception a better and a more remunerative crop was obtained 
with the chemical manure. Farm-yard manure contains on 
an average 80 per cent of water, and, further, about 13 per 
cent of woody fibre and 4 per cent of silica, so that the 
really useful matter is included in the narrow limits of 3 per 
cent. Thus the farmer, in order to apply to his land 
3 lbs. of matter which is needful, has to cart and spread 
97 lbs. of what is valueless. 
According to M. Ville there are in 1 ton of farm-yard 
manure, roughly speaking, 8f lbs. nitrogen, 2-f lbs. phos- 
phoric acid, 8f lbs. potash, and 17J lbs. of lime. If with 
most English agricultural authorities we affix no special value 
to lime, we shall have, say, 20 lbs. of really useful matter ! 
This tiny speck of gold in a mountain of rubbish, so to 
speak, is, according to present prices, worth 10s. 6 d. Con- 
sequently whenever farm-yard manure, stable manure, &c., 
cost more than this sum, including the expense of conveying 
to the field and spreading, their use involves a direct loss. 
A further disadvantage of farm-yard manure is that its 
composition cannot be modified at will to suit the require- 
ments of different crops or different soils. A larger or a 
smaller dose may be given, but the respective proportions of 
potash, of phosphates, and of nitrogen are not under control. 
With chemical manures the intelligent farmer can regulate 
these proportions to a nicety. If he finds that any particular 
field is sufficiently supplied, say, with phosphates, but is de- 
ficient in potash and nitrogen, he can give it a supply of the 
two latter without being compelled at the same time to add 
what is not needed. 
This reminds me of a very common error to which Mr. 
Crookes adverts in a footnote. It is not uncommon to hear 
some such advice given to farmers as this : — “ Do not buy 
chemical manures, but rather some good feeding stuff.” 
This admonition is a survival of the old superstition (for no 
better name does it deserve), that matter by passing through 
the digestive system of an animal receives, in some occult 
way, an efficacy as plant-food which it did not possess before. 
It is all very true that by giving an animal more nutriment 
than it can assimilate, its excrements will have a higher 
manurial value. But there is a first loss in the animal ; the 
whole of the nitrogen swallowed is not recovered in the form 
